Trainer Brian Williamson entered what might be a powerful coupling in Saturday’s $42,500 Mac Diarmida Stakes. The mile and a half grass marathon serves as a final local prep for Arlington’s Grade III Stars and Stripes Breeders’ Cup Turf July 2.

Getting the rail in the draw for Saturday’s featured event was Nancy Vanier and Win Place Show-Me Racing’s Air Academy, who won his last race here over muddy going by 12 ½ lengths May 14.

Near the outside in post position nine of a 10-horse field was Nancy Vanier and Charles Nuckols Jr.’s Come On Jazz, who proved his ability at 12 furlongs over Arlington’s turf course last summer.

“As of now, I plan on running both of them,” said trainer Brian Williamson Thursday morning during training hours, “but I still might change my mind. If I could get a good run out of both on Saturday, that would give us two shots at the Stars and Stripes three weeks later.”

Air Academy has not started on the grass since last Nov. 10 at Churchill Downs, but he won that Marine Corps birthday outing by a half-length. However, the Illinois homebred was racing for a $50,000 tag that day, and it was his only turf win from 14 starts on grass.

Nevertheless, Air Academy is a son of 1990 Breeders’ Cup Mile winner Royal Academy and was the first foal out of the Vanier’s mare Barn Swallow, who won the 1997 Anita Peabody Handicap over Arlington’s lawn.

Come On Jazz, who finished fourth beaten three and a half in Arlington’s $42,500 Mister Gus Stakes May 29, was making his seasonal bow that day but was only beaten three-quarters of a length when runner-up behind S J Stables LLC’s Cloudy’s Knight in Arlington’s $41,500 Rossi Gold Stakes last Sept 3. That Frank Kirby trainee was a facile winner of last year’s $40,000 Mac Diarmida.

“It might be coming back kind of quick for Come On Jazz,” Williamson said, “but he never really had a clear path to run in that last race so it may not have taken too much out of him.”

Arlington’s leading rider Chris Emigh is named aboard both halves of the Williamson-trained coupling.

Although fans of the Arlington Million may zone in on Saturday’s Grade I Manhattan Handicap at Belmont Park for an early look at this summer’s Million candidates, they might also focus on Hollywood Park’s Grade I Charles Whittingham Memorial Handicap later that day.

Out on the west coast, 2006 Arlington Million nominee King’s Drama, an Irish-bred owned by Gary Tanaka and conditioned by Hall of Fame trainer Bobby Frankel, will share the top impost of 122 pounds in the Whittingham after winning Santa Anita’s Grade II San Luis Rey Stakes in March and Saratoga’s Grade I Sword Dancer Invitational last summer.

Also named to the Whittingham are prominent Million nominees such as Tom Baxter’s Fourty Niners Son, conditioned by Hall of Fame trainer Neil Drysdale, third in last year’s Million; Sidney L. Port Trust and San Gabriel Investments’ Artiste Royal, an Irish-bred trained by Laura de Seroux who was sixth in last summer’s Grade III Arlington Handicap; and Red Oak Stable’s British-bred Sweet Return, conditioned by Hall of Fame trainer Ron McAnally, who was seventh in last summer’s Arlington Million.

Denis Savard, a Chicago Blackhawk Hall of Famer as a player and now an assistant coach with that franchise, made his first trip to the Arlington Park winner’s circle as a Thoroughbred owner when Drivingmaxandmitzi, trained by Tom Proctor and ridden by Eddie Martin Jr., won Sunday’s ninth race.

Fittingly, Savard’s racing silks are almost an exact replica of a Blackhawks’ team jersey, with Savard’s retired number 18 displayed prominently on the sleeves.